var express=require('express');
var app=express();

app.get('/',function(req,res){
    res.end('hello world!');
});

var server=app.listen(8081,function(){
    var host=server.address().address
    var port=server.address.port
    console.log('应用实例，访问地址 http://%s:%s',host,port)
});